1. Field of the Invention
The present invention relates to a tire wheel assembly used for a pneumatic tire enabling limited operation in a damaged or flat state (hereinafter referred to as a “run flat tire”). More specifically, it relates to a tire wheel assembly capable of improving the bondability of the contact parts of a ring-shaped metal shell and the rubbery elastic members of a run flat support composed of the ring-shaped metal shell and the rubbery elastic members provided in a tire rim cavity.
2. Description of the Related Art
There is a need for a run flat tire having an emergency running ability capable of running for a certain distance even when the pneumatic tire rapidly drops in the internal pressure due to a flat, blowout, etc. during operation of an automobile. Numerous proposals have been made to meet these needs. As such proposals, for example, Japanese Unexamined Patent Publication (Kokai) No. 10-297226 and Japanese Unexamined Patent Publication (Kokai) No. 2001-519279 propose technology enabling run flat running by attaching a run flat support (i.e., core member) on the rim of the cavity of the pneumatic tire and using this to support a flat etc. pneumatic tire.
This run flat support has a ring-shaped member using its outer circumference as a support surface, attaches elastic rings at the two legs, and has the support supported on the rim through the elastic rings. The technology using a run flat support does not make any particular modifications to the wheel/rim of conventional general pneumatic tires and enables the wheel/rim to be used as they are, and therefore, there is the advantage that the production, processing, and attachment facilities for conventional pneumatic tires can be used as they are.
As opposed to this, as a classical method, there is also the technology of reinforcing the side walls to enable run flat running, but this has the problem that sufficient performance cannot be manifested at tire sizes of a high tire sectional height. Further, as technology providing a core member in the cavity of the tire explained above, there is technology making the core solid, but this has the problem of making assembly difficult since the core lacks flexibility. Further, there are also proposals using special rim structures and special tire structures, but these lack general applicability for both tires and wheels, and therefore, have the problem of placing an excessive burden on the users.
On the other hand, the technology using the above run flat support is superior in general applicability and assembling ability, but the bonding strength of the contact surfaces of the elastic rings and ring-shaped member has a great effect on the durability of the run flat support and greatly governs the durability. Therefore, to improve the durability of the run flat support in a tire wheel assembly mounting a run flat support and extend the run flat running distance, it is necessary to improve the bondability of the metal shell surface and rubbery elastic members of the support.